Valve timing control apparatus

ABSTRACT

A guide passage is provided between a driving-side rotator and a driven-side rotator to supply lubricating fluid into an interior of the first rotator. A planetary gear is received in the driving-side rotator and is meshed with a gear portion of the driving-side rotator to make a planetary motion and thereby to change a relative phase between the driving-side rotator and the driven-side rotator. The guide passage guides the lubricating fluid toward a location on a radially outer side of the gear portion and the planetary gear and has a contaminant capturing space to accumulate contaminants contained in the lubricating fluid.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by reference Japanese Patent Application No. 2007-303474 filed on Nov. 22, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a valve timing control apparatus, which controls valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, which is driven by a camshaft through transmission of a torque from a crankshaft of the internal combustion engine.

2. Description of Related Art

Japanese Unexamined Patent Publication No. 2007-71056 discloses a valve timing control apparatus, in which a planetary gear is meshed with one or more gear portions provided in at least one of a rotator synchronized with a crankshaft and a rotator synchronized with a camshaft. A relative phase between these rotators is changed by a planetary motion of the planetary gear.

In the case of Japanese Unexamined Patent Publication No. 2007-71056, in which the differential gear mechanism that has the planetary gear as its main functional component, is used, the differential gear mechanism, which follows the operational state of the internal combustion engine, is frequently operated. Thus, notable frictional abrasion may occur at the meshed part between the gears of the differential gear mechanism.

In view of this, lubricating fluid is supplied to the rotator synchronized with the crankshaft through a guide hole arrangement provided in the rotator synchronized with the camshaft. Thereby, the meshed part between the gear portion of at least one of these rotators and the planetary gear are lubricated with the lubricating fluid. This lubricating action may improve the durability of the valve timing control apparatus.

In the valve timing control apparatus of Japanese Unexamined Patent Publication No. 2007-71056, the lubricating fluid, which passes from the guide hole arrangement into the interior of the valve timing control apparatus, is supplied from an oil passage that is placed on the center side in the camshaft. Therefore, the lubricating fluid tends to flow from the radially inner side toward the radially outer side and is accumulated at, for example, in the meshed part between the gear portion and the planetary gear.

In this type of structure, in which the lubricating fluid tends to be accumulated in the meshed part between the gears, when the lubricating fluid, which contains abrasive contaminants, is supplied, the abrasion of the meshed part tends to be accelerated. Thus, the lifetime of the valve timing control apparatus may possibly be deteriorated by the abrasion.

At the camshaft side, i.e., at the lubricating fluid supply source of the internal combustion engine, the lubricating fluid is filtered through an oil filter. Therefore, the relatively clean lubricating fluid is supplied to the valve timing control apparatus. However, minute contaminants (e.g., abrasion debris), which are smaller than the mesh size of the oil filter, are directly supplied into the valve timing control apparatus. Therefore, it is difficult to lubricate the meshed part between the gear portions in the valve timing control apparatus. Also, the abrasive debris may possibly be generated due to a damage of a component of the internal combustion engine and may possibly be introduced into the oil passage between the valve timing control apparatus and the oil filter at the lubricating fluid supply source.

SUMMARY OF THE INVENTION

The present invention is made in view of the above disadvantage. Thus, it is an objective of the present invention to provide a valve timing control apparatus, which exhibits improved durability. It is another objective of the present invention to provide a valve timing control apparatus, which can improve its durability while achieving a relatively high productivity thereof.

In order to achieve the objectives of the present invention, there is provided a valve timing control apparatus that controls valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, which is driven by a camshaft through transmission of a torque from a crankshaft of the internal combustion engine to open and close the at least one of the intake valve and the exhaust valve. The valve timing control apparatus includes a first rotator, a second rotator, a guide passage, at least one gear portion and a planetary gear. The first rotator is rotated synchronously with one of the crankshaft and the camshaft. The second rotator is received in the first rotator and is rotated synchronously with the other one of the crankshaft and the camshaft. The guide passage is provided in at least one of the first rotator and the second rotator to supply lubricating fluid, which is received from a lubricating fluid supply source of the internal combustion engine through the camshaft, into an interior of the first rotator. The at least one gear portion is provided in at least one of the first rotator and the second rotator. The planetary gear is received in the first rotator and is meshed with a corresponding one of the at least one gear portion to make a planetary motion and thereby to change a relative phase between the first rotator and the second rotator. The guide passage guides the lubricating fluid toward a location on an outer side of the at least one gear portion and the planetary gear and has a space to accumulate contaminants contained in the lubricating fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:

FIG. 1 is a cross sectional view taken along line I-I in FIG. 3, showing a basic structure of a valve timing control apparatus according to a first embodiment of the present invention;

FIG. 2 is a cross sectional view taken along line II-II in FIG. 1;

FIG. 3 is a cross sectional view taken along line III-III in FIG. 1;

FIG. 4 is a cross sectional view taken along line IV-IV in FIG. 1;

FIG. 5 is a cross sectional view taken along line V-V in FIG. 1;

FIG. 6 is a partial cross sectional view showing a main feature of the valve timing control apparatus shown in FIG. 1;

FIG. 7 is a partial exploded diagram showing a surface portion of a second rotator shown in FIG. 6;

FIG. 8 is a partial cross sectional view showing a valve timing control apparatus according to a second embodiment of the present invention;

FIG. 9 is a partial exploded diagram showing a surface portion of a driving-side rotator shown in FIG. 8;

FIG. 10 is a partial exploded diagram showing a surface portion of a driving-side rotator of a valve timing control apparatus according to a third embodiment of the present invention;

FIG. 11 is a partial cross sectional view showing a valve timing control apparatus according to a fourth embodiment of the present invention;

FIG. 12 is a partial cross sectional view showing a valve timing control apparatus according to a fifth embodiment of the present invention;

FIG. 13 is a partial cross sectional view showing a valve timing control apparatus according to a sixth embodiment of the present invention; and

FIG. 14 is a partial cross sectional view showing a valve timing control apparatus according to a seventh embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, similar components will be indicated by the same reference numerals and will not be repeatedly described.

First Embodiment

FIGS. 1 to 7 show a valve timing control apparatus 1 according to a first embodiment of the present invention. The valve timing control apparatus 1 is installed in a vehicle and is placed in a transmission system, which transmits an engine torque from a crankshaft (not shown) of an internal combustion engine to a camshaft 2. In the present embodiment, the camshaft 2 drives intake valves (not shown) of the internal combustion engine, and the valve timing control apparatus 1 adjusts the valve timing of the intake valves.

As shown in FIG. 1, the valve timing control apparatus 1 includes an electric motor unit 4 and a phase adjusting mechanical unit 8.

The motor unit 4 includes an electric motor 5 and an electric power supply control unit (control circuit unit) 60. The electric motor 5 is, for example, a brushless motor and includes a rotatable shaft 7. The electric motor 5 applies a control torque to the rotatable shaft 7 upon energization thereof to drive the rotatable shaft 7 in a clockwise direction or a counterclockwise direction in FIG. 2. The electric power supply control unit 60 includes, for example, a control computer and a power supply driver and may be placed outside and/or inside of the electric motor 5. The electric power supply control unit 60 is electrically connected to the electric motor 5. The electric power supply control unit 60 controls electric power supply to the electric motor 5 to control a rotational state of the rotatable shaft 7.

The phase adjusting mechanical unit 8 includes a driving-side rotator (serving as a first rotator) 10, a driven-side rotator (serving as a second rotator) 20, a planetary carrier 40 and a planetary gear 50.

As shown in FIGS. 1 to 3, the driving-side rotator 10 is configured into a cylindrical tubular body and receives the other constituent components 20, 40, 50 of the phase adjusting mechanical unit 8. The driving-side rotator 10 includes a cup-shaped gear member 12 and a cup-shaped sprocket 13, which are coaxially connected together with screws.

A driving-side gear portion 14 is formed in a peripheral wall of the gear member 12 and has an addendum circle, which is placed radially inward of a deddendum circle thereof. A plurality of teeth 16 is formed in a peripheral wall of the sprocket 13. The teeth 16 project radially outwardly and are arranged one after another in a rotational direction of the sprocket 13. An annular timing chain is placed around the teeth 16 of the sprocket 13 and teeth of the crankshaft to rotate synchronously with the crankshaft. Thus, when the engine torque is supplied from the crankshaft to the sprocket 13 through the timing chain, the driving-side rotator 10 is rotated synchronously with the crankshaft. At this time, a rotational direction of the driving-side rotator 10 is a counterclockwise direction in FIG. 2 and is a clockwise direction in FIG. 3.

As shown in FIGS. 1 and 3, the driven-side rotator 20 is configured into a generally cylindrical cup shape and is coaxially received in the driving-side rotator 10. A bottom wall of the driven-side rotator 20 forms a connecting portion 21, which is coaxially connected to the camshaft 2 with screws. Through this connection, the driven-side rotator 20 is rotated together with the camshaft 2 relative to the driving-side rotator 10 in an advancing direction X or a retarding direction Y.

The peripheral wall of the driven-side rotator 20 forms a driven-side internal gear portion 22, which has an addendum circle on a radially inner side of a deddendum circle thereof. Here, an inner diameter of the driven-side internal gear portion 22 is smaller than an inner diameter of the driving-side internal gear portion 14. Furthermore, the number of teeth of the driven-side internal gear portion 22 is smaller than the number of teeth of the driving-side internal gear portion 14. The driven-side internal gear portion 22 is displaced from the driving-side internal gear portion 14 in the axial direction.

As shown in FIGS. 1 to 3, the planetary carrier 40 is configured into a cylindrical tubular body and has an input portion 41 at an inner peripheral surface of the planetary carrier 40. The input portion 41 is coaxial with respect to the driving-side rotator 10 and the driven-side rotator 20 and is connected to the rotatable shaft 7. Specifically, as shown in FIG. 2, two engaging grooves 42 are formed in the input portion 41. A joint 43 is securely fixed to the rotatable shaft 7 through, for example, a pin (not shown). Two radial projections of the joint 43 are fitted into the engaging grooves 42, respectively, to conned between the rotatable shaft 7 and the input portion 41 and thereby to rotate together with the input portion 41. In this way, the planetary carrier 40 can rotate integrally with the rotatable shaft 7 in response to the generation of the drive torque and can rotate relative to the driving-side internal gear portion 14 in the advancing direction X or the retarding direction Y.

Furthermore, an eccentric portion 44, which is eccentric to the input portion 41, is formed by an outer peripheral part of the planetary carrier 40. The eccentric portion 44 is installed to the inner peripheral side of the center hole 51 of the planetary gear 50 through a bearing 45. The planetary gear 50 is supported by the eccentric portion 44 in such a manner that the planetary gear 50 makes planetary motion in response to the relative rotation of the planetary carrier 40 relative to the driving-side internal gear portion 14. Here, the planetary motion of the planetary gear 50 is made such that the planetary gear 50 revolves in the rotational direction of the planetary carrier 40 while the planetary gear 50 rotates about the eccentric axis of the eccentric portion 44.

The planetary gear 50 is formed into a stepped cylindrical body. Specifically, the planetary gear 50 has a large diameter portion, which forms a driving-side external gear portion 52, and a small diameter portion, which forms a driven-side external gear portion 54. The driving-side external gear portion 52 has an addendum circle on the radially outward of a deddendum circle thereof. Similarly, the driven-side external gear portion 54 has an addendum circle on the radially outward of a deddendum circle thereof. The number of teeth of the driving-side external gear portion 52 is smaller than that of the driving-side internal gear portion 14 by a predetermined number, and the number of teeth of the driven-side external gear portion 54 is smaller than that of the driven-side internal gear portion 22 by the same predetermined number. The driving-side external gear portion 52 is placed radially inward of the driving side internal gear portion 14 and is meshed with the driving side internal gear portion 14. The driven-side external gear portion 54, which is located on the connecting portion 21 side of the driving-side external gear portion 52, is placed radially inward of the driven-side internal gear portion 22 and is meshed with the driven-side internal gear portion 22.

As discussed above, the phase adjusting mechanical unit 8 of the differential gear type, in which the driving-side rotator 10 and the driven-side rotator 20 are interconnected, conducts the cam torque of the camshaft 2 to the rotatable shaft 7 and adjusts the relative phase between the driving-side rotator 10 and the driven-side rotator 20 based on the rotational state of the rotatable shaft 7.

Specifically, when the rotatable shaft 7 is rotated in a normal rotational direction (the rotational direction of the crankshaft in this embodiment) at the same rotational speed as that of the driving-side rotator 10, the planetary carrier 40 does not rotate relative to the driving-side internal gear portion 14. At that time, the planetary carrier 40 does not make the planetary motion and is rotated together with the driving-side rotator 10 and the driven-side rotator 20. That is, since the relative phase between the driving-side rotator 10 and the driven-side rotator 20 does not change, the current valve timing is maintained.

In contrast, when the rotatable shaft 7 is rotated in the normal rotational direction at the higher rotational speed, which is higher than that of the driving-side rotator 10, the planetary carrier 40 is rotated relative to the driving-side internal gear portion 14 in the advancing direction X. At that time, the driven-side rotator 20 is rotated relative to the driving-side rotator 10 in the advancing direction X by the planetary motion of the planetary gear 50. That is, since the relative phase between the driving-side rotator 10 and the driven-side rotator 20 changes in the advancing direction X, the valve timing is advanced in response to the change in the relative phase.

In contrast, when the rotatable shaft 7 is rotated in the normal rotational direction or the reverse rotational direction at the lower rotational speed, which is lower than that of the driving-side rotator 10, the planetary carrier 40 is rotated relative to the driving-side internal gear portion 14 in the retarding direction Y. At that time, the driven-side rotator 20 is rotated relative to the driving-side rotator 10 in the retarding direction Y by the planetary motion of the planetary gear 50. That is, since the relative phase between the driving-side rotator 10 and the driven-side rotator 20 changes in the retarding direction Y, the valve timing is retarded in response to the change in the relative phase.

The basic structure of the first embodiment has been described above. Now, the characteristic structure of the first embodiment will be described.

As shown in FIGS. 1 and 6, the sprocket 13 of the driving-side rotator 10 includes a support hole 15. The support hole 15 opens to an end surface of the sprocket 13, which is opposite from the gear member 12. The support hole 15 is configured into cylindrical tubular body, which has an inner diameter that is smaller than the addendum circle of the driving-side internal gear portion 14 and the addendum circle of the driven-side internal gear portion 22. Furthermore, the support hole 15 is displaced from the driving-side internal gear portion 14 and the driven-side internal gear portion 22 in the axial direction. In the present embodiment, the support hole 15 is placed on the opposite side of the driven-side internal gear portion 22, which is opposite from the driving-side internal gear portion 14 of the gear member 12 in the axial direction.

Furthermore, an inner peripheral wall of the support hole 15 is rotatably supported by the camshaft 2, and the support hole 15 is placed coaxial with the driven-side rotator 20, which is fixed to a connecting portion 6 of the camshaft 2 with screws. Specifically, the camshaft 2 supports the inner peripheral wall of the support hole 15 from a radially inner side of the support hole 15 such that a relatively high radial positioning accuracy between the driving-side rotator 10 and the driven-side rotator 20 is maintained while enabling the relative rotation between the driving-side rotator 10 and the driven-side rotator 20.

Specifically, an axial outer end surface 24 of the connecting portion 21 of the driven-side rotator 20 is securely fixed to the connecting portion 6 of the camshaft 2 with screws such that the connecting portion 21 of the driven-side rotator 20 is positioned coaxial to the connecting portion 6 of the camshaft 2. The outer end surface 24 of the connecting portion 21 integrally contacts a camshaft-side contact surface 61 of the connecting portion 6 and is placed adjacent to an axial inner end surface 18 of the sprocket 13 in a manner that enables rotation of the outer end surface 24 relative to the inner end surface 18 of the sprocket 13.

In the driving-side rotator 10, the sprocket 13 includes a driving-side stepped portion 17, which connects between the support hole 15 and the driving-side internal gear portion 14 of the gear member 12. The driving-side stepped portion 17 includes the inner end surface 18 of an annular shape and an inner peripheral surface 11 of a cylindrical shape. The inner end surface 18 is axially opposed to the outer end surface 24 of the driven-side rotator 20. The inner peripheral surface 11 is radially opposed to an outer peripheral surface 25 of the driven-side rotator 20.

The inner end surface 18 and the inner peripheral surface 11 of the sprocket 13 of the driving-side rotator 10 collectively serve as a surface portion of a first rotator of the present invention. Furthermore, the outer end surface 24 and the outer peripheral surface 25 of the driven-side rotator 20 collectively serve as a surface portion of a second rotator of the present invention.

Furthermore, as shown in FIGS. 1 and 4, the sprocket 13 includes a plurality of stopper grooves 70-72, which are formed as engaging recesses along the inner peripheral surface 11 of the sprocket 13 and are arranged one after another at predetermined intervals in the circumferential direction. The gear member 12 is installed into the sprocket 13 in the axial direction and is fixed to the sprocket 13 with the screws, so that stopper recesses 76-78 are formed in the stopper grooves 70-72, respectively.

Also, the driven-side rotator 20 includes a plurality of stopper projections 73-75, which project radially outward from the driven-side rotator 20 and are arranged one after another at predetermined intervals to serve as engaging projections. The stopper projections 73-75 are received in the stopper grooves 70-72, respectively, at the radially outer side of the driving-side rotator 10 in a manner that allows a swing motion between the driving-side rotator 10 and the driven-side rotator 20 in the circumferential direction. In the state where the stopper projections 73-75 are received in the stopper grooves 70-72, respectively, a stopper surface of at least one of the stopper grooves 70-72 abuts against, i.e., is circumferentially engaged with a stopper surface of the corresponding stopper projection 73-75 to limit the relative phase between the driving-side rotator 10 and the driven-side rotator 20. In the present embodiment, only the stopper surface of the stopper groove 70 is circumferentially engaged with the stopper surface of the stopper projection 73 while the stopper surface of each of the other remaining grooves 71-72 is not circumferentially engaged with the stopper surface of the corresponding stopper projection 74-75.

Here, the stopper groove 71 and the corresponding stopper projection 74 as well as the stopper groove 72 and the stopper projection 75 are redundant and are provided for fail-safe purpose in the case of failure of the stopper groove 70 and the stopper projection 73.

As shown in FIGS. 1 and 6, a guide passage 80 is defined between the driving-side rotator 10 and the driven-side rotator 20 to guide lubricating oil (serving as lubricating fluid) into the interior of the driving-side rotator 10. The lubricating oil is supplied to the guide passage 80 from a lubricating oil supply source (lubricating fluid supply source) of the internal combustion engine to lubricate the gear portions 14, 22, 52, 54 of the driving-side rotator 10 and the driven-side rotator 20. The guide passage 80 includes a guide hole arrangement 81 and a contaminant capturing space 82.

The guide hole arrangement 81, which includes a plurality of communicating holes as throttling portions 81 a (described below in detail), is provided in the connection between the connecting portion 21 of the driven-side rotator 20 and the connecting portion 6 of the camshaft 2 and. The throttling portions 81 a are always communicated with supply holes 3 (only one is shown in FIG. 6), respectively, of the camshaft 2. Specifically, the guide hole arrangement 81 includes a plurality of recesses, which form the throttling portions 81 a, respectively, and are recessed in a part the outer end surface 24 of the connecting portion 21 of the driven-side rotator 20, which is axially opposed to the camshaft-side contact surface 61 of the camshaft 2.

Here, each supply hole 3 forms a passage, to which the lubricating oil is supplied from a pump 9 (serving as the lubricant fluid supply source) of the internal combustion engine. The pump 9 is a mechanical pump, which is mechanically driven by the engine torque that is outputted from the internal combustion engine. The pump 9 should not be limited to the mechanical pump. For example, the pump 9 may be a variable displacement pump, which can vary a discharge volume of the lubricating oil regardless of the operational state of the internal combustion engine. Further alternatively, the pump 9 may be an electric pump.

As shown in FIGS. 1, 5 and 6, the guide hole arrangement 81 (more specifically, the throttling portions 81 a) opens in the outer end surface 24, which is opposed to the camshaft-side contact surface 61 of the camshaft 2 and the inner end surface 18 of the driving-side rotator 10. As described above, the guide hole arrangement 81 includes the throttling portions 81 a, each of which is formed as the recess that is axially recessed in the outer end surface 24 of the connecting portion 21 of the driven-side rotator 20 to create the communicating hole or passage. The throttling portions 81 a limit a flow quantity of the lubricating oil, which is supplied into to the interior of the driving-side rotator 10, to a predetermined flow quantity. When the lubricating oil passes the throttling portions 81 a, the flow quantity of the lubricating oil is limited by the action of the throttling portions 81 a. Thus, the flow quantity of the lubricating oil (hereinafter, referred to as a lubricating oil quantity) is minimized to limit the influence on the lubrication of other devices of the internal combustion engine, which is other than the valve timing control apparatus 1. Here, the action of each of the throttling portions 81 a is to reduce a flow passage cross sectional area, through which the lubricating oil flows, in comparison to a flow passage cross sectional area at an upstream side of the throttling portion 81 a. Thus, the lubricating oil quantity, which is supplied on the downstream side of the throttling portions 81 a, is adjusted by the throttling portions 81 a.

The contaminant capturing space 82 is located on the downstream side of the guide hole arrangement 81 in the guide passage 80 at radially outward of the guide hole arrangement 81 to supply the lubricating oil toward the gear portions 14, 22, 52, 54. The contaminant capturing space 82 extends radially outward to guide the lubricating oil from the radially inner side toward the radially outer side at the driving-side rotator 10 and the driven-side rotator 20. Thus, the lubricating oil, which contains contaminants (e.g., debris, dust, dirt), is separated into the contaminants and the lubricating oil in the contaminant capturing space 82 by the centrifugal force, which is generated upon rotation of the driving-side rotator 10 and the driven side rotator 20. In the contaminant capturing space 82, the separated contaminants tend to be accumulated at the inner wall side of the contaminant capturing space 82 rather than the center side region of the contaminant capturing space 82, through which the lubricating oil flows. Therefore, the guide passage 80 supplies the filtered lubricating oil (relatively clean lubricating oil), from which the contaminants are substantially removed at the contaminant capturing space 82, to the gear portions 14, 22, 52, 54 to lubricate the same with the relatively clean lubricating oil.

Particularly, in the present embodiment, as shown in FIG. 6, the contaminant capturing space 82 is formed on the outer side of the driven-side rotator 20 and on the inner side of the driving-side rotator 10 upon installation of the driven side rotator 20 into the driving-side rotator 10. Specifically, the contaminant capturing space 82 is defined in the gap between the surface portion (hereinafter, referred to as a first surface portion) 11, 18 of the driving-side rotator 10 and the surface portion (hereinafter, referred to as a second surface portion) 24, 25 of the driven-side rotator 20.

The contaminant capturing space 82 forms a generally annular space, i.e., gap between the inner peripheral surface 11 (the first surface portion) of the driving-side rotator 10 and the outer peripheral surface 25 (the second surface portion) of the driven-side rotator 20. The lubricating oil, which is supplied through the guide hole arrangement 81, flows into this generally annular gap of the contaminant capturing space 82. Thus, the contaminants are forced toward the inner peripheral surface 11, which defines the one radial side of the generally annular space, by the centrifugal force to effectively accumulate the contaminants on the inner peripheral surface 11.

Furthermore, as shown in FIGS. 6 and 7, a recess 83, which is axially opposed to the guide hole arrangement 81 side of the outer end surface 24, is formed in the inner end surface 18 and extends to the inner peripheral surface 11. Specifically, in the inner end surface 18 and the inner peripheral surface 11, the recess 83 is defined between an inner peripheral side (inner peripheral edge) 83 a of the inner end surface 18, which overlaps with a radial extent of the guide hole arrangement 81 of the outer end surface 24 in the radial direction, and an upstream side (upstream side edge) 83 b of the respective stopper grooves 70-72.

In this way, in the area between the inner peripheral side 83 a and the upstream side 83 b, the contaminant capturing space 82 has the sufficient flow passage cross sectional area in the circumferential direction on the outer side of the outer peripheral surface 25 and the outer end surface 24 of the driven-side rotator 20. In the contaminant capturing space 82, which has the sufficient flow passage cross sectional area for conducting the lubricating oil, even when the contaminants are accumulated in the contaminant capturing space 82 to cause the reduction in the flow passage cross sectional area, the sufficient flow passage cross sectional area is still left. Therefore, it is possible to maintain the good state for lubricating the gear portions 14, 22, 52, 54 of the phase adjusting mechanical unit 8 with the relatively clean lubricating oil, from which the contaminants are removed in the contaminant capturing space 82.

In the present embodiment, the contaminant capturing space 82 is formed by the outer side second surface portion 24, 25 and the adjacent inner side second surface portion 11, 18 at the driving-side rotator 10 and the driven-side rotator 20. At the location between the first surface portion 11, 18 and the second surface portion 24, 25, the gap (hereinafter, referred to as a stopper gap) 84 is formed between each of the stopper projections 73-75 and the corresponding stopper recess 76-78 to form a part (a downstream end part in the present embodiment) of the contaminant capturing space 82. The lubricating oil, which flows out from the stopper gap 84, creates the flow against the centrifugal force from the location on the radially outer side of the gear portions 14, 22, 52, 54 toward the inner side of the gear portions 14, 22, 52, 54. In other words, the stopper gap 84 guides the lubricating oil from the location on the radially outer side of the gear portions 14, 22, 52, 54 toward the inner side on the downstream side of the contaminant capturing space 82. Thereby, it is possible to limit the outflow of the contaminants from the contaminant capturing space 82 toward the gear portions 14, 22, 52, 54.

In the present embodiment, the guide hole arrangement 81 and the contaminant capturing space 82 of the guide passage 80 are formed between the first surface portion 11, 18 and the second surface portion 24, 25. Therefore, it is not required to form a hole that extends through the driving-side rotator 10 and the driven-side rotator 20. Specifically, the guide passage 80 of the present embodiment can be formed through a sintering process, a forging process or a press working process, which are other than a drilling process and a cutting process. For example, in the case of forming the sprocket 13 of the driving-side rotator 10 and the driven-side rotator 20 through the forging process, the recess 83 in the inner end surface 18 and the inner peripheral surface 11 of the sprocket 13 as well as the outer end surface 24 and the outer peripheral surface 25 of the driven-side rotator 20 are simultaneously formed by the forging process without a need for performing any cutting process.

Here, the contaminant capturing space 82 serves as a space of the present invention. Furthermore, the sprocket 13 and the gear member 12 of the driving-side rotator 10 serve as an assembled rotator of the present invention. The sprocket 13 serves as a supporting body of the present invention, and the gear member 12 serves as a fixing body of the present invention. Furthermore, the stopper grooves 70-72 serve as support openings of the present invention. In addition, the stopper recesses 76-78 serve as engaging recesses of the present invention, and the stopper projections 73-75 serve as engaging projections of the present invention.

Furthermore, the recess 83 formed in the first surface portion 11, 18 and the stopper recesses 76-78 serve as recesses of the present invention.

In the present embodiment, as discussed above, the guide passage 80 includes the contaminant capturing space 82. The contaminant capturing space 82 guide the lubricating oil, which is supplied into the guide passage 80, toward the outer side of the gear portions 14, 22, 52, 54. Furthermore, at the outer side of the gear portions 14, 22, 52, 54, the contaminant capturing space 82 forms the contaminant accumulating portion, at which the contaminants contained in the lubricating oil are accumulated. In this way, the lubricating oil, which is supplied into the guide passage 80, flows through the foreign contaminant capturing space 82, at which the foreign contaminants contained in the lubricating oil are removed. Thus, the relatively clean lubricating oil, from which the foreign contaminants are removed, is supplied to the meshed teeth of the gear portions 14, 22, 52, 54. Furthermore, at the contaminant capturing space 82, the contaminants can be removed from the lubricating oil through the application of the centrifugal force. Thereby, the contaminants, which are removed from the lubricating oil, are effectively accumulated and deposited in the contaminant capturing space 82.

Furthermore, in the present embodiment, the driven-side rotator 20 is received in the driving-side rotator 10. The contaminant capturing space 82 is formed between the first surface portion 11, 18 and the second surface portion 24, 25, which are placed adjacent to each other at the driving-side rotator 10 and the driven-side rotator 20. That is, the gap, which is formed upon installation of the driven-side rotator 20 into the driving-side rotator 10, becomes the contaminant capturing space 82. In other words, the contaminant capturing space 82, which has the function of accumulating the contaminants of the lubricating oil, can be implemented by the relatively simple gap. Furthermore, at the time of manufacturing the valve timing control apparatus 1, the contaminant capturing space 82 can be created by simply installing the driven-side rotator 20 into the driving-side rotator 10.

Furthermore, in the present embodiment, at the first surface portion 11, 18 and the second surface portion 24, 25, the contaminant capturing space 82 is placed at least between the inner peripheral surface 11 of the driving-side rotator 10 and the outer peripheral surface 25 of the driven-side rotator 20 to form the annular gap. When the lubricating oil, which is supplied into the guide passage 80, flows into this annular gap of the contaminant capturing space 82, the contaminants are effectively accumulated at the inner peripheral surface 11 side of the annular gap through the application of the centrifugal force, and thereby the contaminants are deposited at the inner peripheral surface 11.

Furthermore, in the present embodiment, at the guide passage 80, the contaminant capturing space 82 and the guide hole arrangement 81 are formed between the first surface portion 11, 18 and the second surface portion 24, 25. Also, at the first surface portion 11, 18, the throttling portions 81 a of the guide hole arrangement 81 are formed in the outer end surface 24, which contacts the camshaft-side contact surface 61 of the camshaft 2, such that each of the throttling portions 81 a is configured into the recess that is recessed in the outer end surface 24 and is opened toward the camshaft-side contact surface 61.

In the guide passage 80, the guide hole arrangement 81 and the contaminant capturing space 82 are provided between the first surface portion 11, 18 of the driving-side rotator 10 and the second surface portion 24, 25 of the driven-side rotator 20 to conduct the lubricating oil between the first surface portion 11, 18 and the second surface portion 24, 25. The guide passage 80, which includes the guide hole arrangement 81 and the contaminant capturing space 82, can be provided without requiring the mechanical process, such as the hole forming process (the drilling process) for forming the hole that penetrates through the driving-side rotator 10 and/or the driven-side rotator 20 unlike the prior art technique. Thus, the productivity of the valve timing control apparatus 1 can be improved.

Here, in the guide passage 80, the lubricating oil, which is supplied through the camshaft 2, flows into the contaminant capturing space 82 through the guide hole arrangement 81. Since the flow passage cross sectional area of the contaminant capturing space 82 becomes smaller as the amount of contaminants accumulated in the contaminant capturing space 82 increases, it is desirable to set the relatively large flow passage cross sectional area of the contaminant capturing space 82.

In the present embodiment, the throttling portions 81 a, which reduce the flow passage cross sectional area for conducting the lubricating oil, are provided in the guide hole arrangement 81 located on the upstream side of the contaminant capturing space 82. Thus, the flow passage cross sectional area of the contaminant capturing space 82 can be relatively easily increased while limiting the influence on the lubrication of the internal combustion engine. Also, it is possible to implement the long lasting contaminant capturing function of the contaminant capturing space 82.

Also, in the present embodiment, at the guide passage 80, the lubricating oil is guided from the location on the radially outer side of the gear portions 14, 22, 52, 54 toward the radially inner side against the centrifugal force on the downstream side of the contaminant capturing space 82. The lubricating oil, which exits from the contaminant capturing space 82, flows to the gear portions 14, 22, 52, 54 against the centrifugal force. Therefore, the contaminants, which have the relatively large density (relatively large relative density), are limited from flowing out of the contaminant capturing space 82 toward the gear portions 14, 22, 52, 54.

Furthermore, in the present embodiment, the lubricating oil is guided from the location on the radially outer side of the gear portions 14, 22, 52, 54 on the downstream side of the contaminant capturing space 82. Also, the stopper projections 73-75 are formed in the outer peripheral surface 25 of the driven-side rotator 20 at the downstream side end part of the outer peripheral surface 25 of the driven-side rotator 20, and the stopper recesses 76-78 are formed at the downstream side end part of the inner peripheral surface 11 of the sprocket 13 of the driving-side rotator 10. Furthermore, the stopper gap 84 is formed between each stopper projection 73-75 and the corresponding stopper recess 76-78. At the stopper gap 84, it is possible to reliably implement the structure for guiding the lubricating oil from the location on the radially outer side of the gear portions 14, 22, 52, 54 toward the radially inner side on the downstream side of the contaminant capturing space 82 (hereinafter, referred to as a lubricating oil guide function).

Furthermore, when the lubricating oil passes through the stopper gap 84, the contaminants are effectively accumulated and deposited in the stopper recesses 76-78.

Here, it is desirable to guide the lubricating oil to the stopper recesses 77, 78 of FIG. 7, which are redundantly provided for the fail-safe purpose among the stopper recesses 76-78 and the corresponding stopper projections 73-75. In this way, it is possible to limit the influence of the contaminants on the limiting function, which is implemented by the stopper recess 71 and the stopper projection 73 while implementing the lubricating oil guide function of the stopper recesses 77, 78 and the stopper projections 74, 75.

The stopper projections 73-75 and the stopper recesses 76-78 have the above-described limiting function to limit the variable range of the relative phase between the driving-side rotator 10 and the driven-side rotator 20 upon installation of the stopper projections 73-75 into the stopper recesses 76-78, respectively, in a manner that allows the rotation (the swing motion) of the respective stopper projections 73-75 within the predetermined circumferential range (predetermined swing range). The redundant stopper recesses 77, 78 and the corresponding stopper projections 74, 75 have the fail-safe liming function, which becomes effective at the time of failure of the stopper recess 76 and the stopper projection 73.

Some previously proposed valve timing control apparatuses have the above limiting function to limit the variable range of the relative phase. In a case where the valve timing control apparatus 1 of the present embodiment is implemented in such an apparatus, the structure of limiting the outflow of the contaminants from the contaminant capturing space 82 to the gear portions 14, 22, 52, 54 can be obtained without requiring any new additional component.

Furthermore, in the present embodiment, the recess 83 is formed in the inner peripheral surface 11 of the generally annular gap defined between the first surface portion 11, 18 and the second surface portion 24, 25. Thus, the contaminant capturing space 82, which accumulates the contaminants contained in the lubricating oil, can be reliably formed.

Second Embodiment

A second embodiment of the present invention, which is a modification of the first embodiment, will be described with reference to FIGS. 8 and 9. In the second embodiment, a plurality of protrusions 85, each of which is configured into a generally cylindrical body, is provided in the recess 83, which is formed by the inner end surface 18 and the inner peripheral surface 11 in the contaminant capturing space 82.

As shown in FIG. 9, the recess 83 is formed in the inner end surface 18 and the inner peripheral surface 11 of the sprocket 13 in the area between the inner peripheral side 83 a and the upstream side 83 b. The protrusions 85 radially inwardly project from the surface of the recess 83 in the range of the generally annular gap. Specifically, in the present embodiment, the protrusions 85 contact the outer peripheral surface 25 of the driven-side rotator 20, and the radial size of the generally annular gap is defined by the amount of projection of the respective protrusions 85. As shown in FIG. 9, the protrusions 85 are arranged into multiple rows, which are placed one after another in the flow direction of the lubricating oil, i.e., in the axial direction. In each row, the protrusions 85 are arranged at generally equal intervals in the circumferential direction of the driving-side rotator 10. The protrusions 85 of one of the rows are staggered relative to the protrusions 85 of a next one of the rows.

The flow of the lubricating oil in the recess 83 is directed in the upward direction in FIG. 9 through the guide hole arrangement 81. The protrusions 85, which are placed in the recess 83 in a manner shown in FIG. 9, act as obstacles, which change the flow direction of the lubricating oil in the recess 83.

At the time of conducting the lubricating oil around the protrusions 85, the flow of the contaminants is hindered while the flow of the lubricating oil itself is kept relatively smooth. Therefore, the contaminants can be effectively accumulated in the contaminant capturing space 82.

Third Embodiment

A third embodiment of the present invention, which is a modification of the first embodiment, will be described with reference to FIG. 10. In the third embodiment, a plurality of protrusions 85, each of which is configured into a generally planar quadrangular prism body, is provided in the recess 83 that is formed by the inner end surface 18 and the inner peripheral surface 11 in the contaminant capturing space 82.

As shown in FIG. 10, the protrusions 85 are arranged in multiple rows, which are placed one after another in the flow direction of the lubricating oil, i.e., in the axial direction. In each row, the protrusions 85 are arranged at generally equal intervals in the circumferential direction of the driving-side rotator 10. The protrusions 85 of one of the rows are staggered relative to the protrusions 85 of a next one of the rows. The protrusions 85, each of which is configured into the generally planar quadrangular prism body, act as baffle plates that hinder the flow of the lubricating oil. In this way, the flow of the contaminants is hindered in the greater degree in comparison to the flow of the lubricating oil itself. Thus, the contaminants are accumulated at the upstream side wall surface of the respective protrusions 85, which act as the baffle plates, and thereby the contaminants are effectively deposited.

Fourth Embodiment

A fourth embodiment of the present invention, which is a modification of the first embodiment, will be described with reference to FIG. 11. In the fourth embodiment, the protrusions 85 are provided in the recess 83, which is formed by the inner end surface 18 and the inner peripheral surface 11 in the contaminant capturing space 82. The projecting amounts of the protrusions 85 are not uniformly set.

As shown in FIG. 11, the generally annular gap is defined by the protrusions 85 a, 85 c, which have the maximum projecting amount. The protrusions 85 b, which have the smaller radial projecting amount in comparison to the protrusions 85 a, 85 c, form minute radial gaps, which are smaller than the generally annular gap described above, relative to the outer peripheral surface 25. The lubricating oil can smoothly flow through the minute gaps while the contaminants cannot flow through the minute gaps. Thus, the flow of the contaminants may be stopped on the upstream side of the minute gaps, or the contaminants may be held in the minute gaps. Therefore, the contaminants can be accumulated and deposited at the protrusions 85 b.

Fifth Embodiment

A fifth embodiment of the present invention, which is a modification of the first embodiment, will be described with reference to FIG. 12. In the fifth embodiment, the protrusions 85 are provided in the recess 83, which is formed in the inner end surface 18 and the inner peripheral surface 11 of the first surface portion, in the contaminant capturing space 82. Furthermore, protrusions 86 are provided in the outer peripheral surface 25 of the second surface portion.

In the present embodiment, as shown in FIG. 12, the projecting amount of the protrusions 86 on the outer peripheral surface 25 is made smaller than that of the projecting amount of the protrusions 85 on the inner peripheral surface 11. That is, the radial size of the generally annular gap is defined by the projecting amount of the protrusions 85, and the radial size of the respective minute gaps is defined by the projecting amount of the respective protrusions 86. In this way, the protrusions 85, 86, which serve as the obstacles, are dispersed at the relatively high density in the contaminant capturing space 82. Therefore, the contaminants in the lubricating oil, which passes the contaminant capturing space 82, can be further effectively accumulated, and thereby the cleanness of the lubricating oil, which exits from the contaminant capturing space 82, is improved.

Sixth Embodiment

A sixth embodiment of the present invention, which is a modification of the first embodiment, will be described with reference to FIG. 13. In the sixth embodiment, a recess 83 is formed in the outer end surface 24 and the outer peripheral surface 25 of the second surface portion in the contaminant capturing space 82.

As shown in FIG. 13, in the guide passage 80, the recess 83 of the guide hole arrangement 81 and of the contaminant capturing space 82 is entirely formed in the second surface portion 24, 25, i.e., in the outer end surface 24 and the outer peripheral surface 25.

Even with this construction, advantages similar to those of the first embodiment can be achieved.

Seventh Embodiment

FIG. 14 shows a seventh embodiment of the present invention. In the seventh embodiment, a branch passage 89 is provided to guide a portion of the lubricating oil from the contaminant capturing space 82 in a different guide direction, which is different from that of the above embodiments.

As shown in FIG. 14, the branch passage 89 is provided in the driven-side rotator 20 to extend through the outer peripheral surface 25 at the contaminant capturing space 82 and an inner end surface of the connecting portion 21. The branch passage 89 guides the lubricating oil toward the gear portions 14, 22, 52, 54, which are placed on the radially outer side of the planetary carrier 40 and are axially displaced from one after another.

In this way, the portion of the lubricating oil is branched through the branch passage 89 in the middle of the contaminant capturing space 82. This branched lubricating oil flows through the contaminant capturing space 82 and is thereby relatively clean. The branched lubricating oil is axially guided through the branch passage 89 from the contaminant capturing space 82 toward the gear portions 14, 22, 52, 54.

In the present embodiment, the lubricating oil, which is cleaned through the contaminant capturing space 82 in the guide passage 80, is divided into the flow of the lubricating oil, which is guided from the location on the radially outer side of the gear portions 14, 22, 52, 54 toward the inner side, and the flow of the lubricating oil, which is guided in the axial direction toward the gear portions 14, 22, 52, 54.

The present invention has been described with respect to the above embodiments. However, the present invention is not limited to the above embodiments, and the above embodiments may be modified within a spirit and scope of the present invention.

The present invention is also applicable to any other type of valve timing control apparatus, which controls valve timing of exhaust valves or which controls both of the valve timing of the intake valves and the valve timing of the exhaust valves.

Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described. 

1. A valve timing control apparatus that controls valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, which is driven by a camshaft through transmission of a torque from a crankshaft of the internal combustion engine to open and close the at least one of the intake valve and the exhaust valve, the valve timing control apparatus comprising: a first rotator that is rotated synchronously with one of the crankshaft and the camshaft; a second rotator that is received in the first rotator and is rotated synchronously with the other one of the crankshaft and the camshaft; a guide passage that is provided in at least one of the first rotator and the second rotator to supply lubricating fluid, which is received from a lubricating fluid supply source of the internal combustion engine through the camshaft, into an interior of the first rotator; at least one gear portion that is provided in at least one of the first rotator and the second rotator; and a planetary gear that is received in the first rotator and is meshed with a corresponding one of the at least one gear portion to make a planetary motion and thereby to change a relative phase between the first rotator and the second rotator, wherein the guide passage guides the lubricating fluid toward a location on an outer side of the at least one gear portion and the planetary gear and has a space to accumulate contaminants contained in the lubricating fluid.
 2. The valve timing control apparatus according to claim 1, wherein the space is provided between a surface portion of the first rotator and a surface portion of the second rotator, which are placed adjacent to each other.
 3. The valve timing control apparatus according to claim 2, wherein the space is formed at least between an inner peripheral surface of the surface portion of the first rotator and an outer peripheral surface of the surface portion of the second rotator.
 4. The valve timing control apparatus according to claim 2, wherein at least one of a recess and a protrusion is formed in at least one of the surface portion of the first rotator and the surface portion of the second rotator.
 5. The valve timing control apparatus according to claim 2, wherein the guide passage includes a guide hole arrangement that includes at least one communicating hole and opens on a radially inner side of the space at an end surface of the surface portion of at least one of the first rotator and the second rotator, which contacts the camshaft.
 6. The valve timing control apparatus according to claim 5, wherein the at least one communicating hole of the guide hole arrangement is formed as at least one throttling portion that has a reduced flow passage cross sectional area, which is smaller than a flow passage cross sectional area located on an upstream side of the throttling portion, to conduct the lubricating fluid in the guide passage.
 7. The valve timing control apparatus according to claim 1, wherein the guide passage guides the lubricating fluid from the location on the outer side of the at least one gear portion and the planetary gear toward an inner side of the at least one gear portion and the planetary gear on a downstream side of the space.
 8. The valve timing control apparatus according to claim 1, wherein: the first rotator is an assembled rotator that includes an engaging recess, which is connected with an engaging projection that radially projects from the second rotator; the assembled rotator includes a fixing body and a supporting body, which are axially separable at the engaging recess; the supporting body includes a support opening that opens at a dividing end surface of the supporting body, which contacts the fixing body, in the engaging recess and supports the engaging projection; and the fixing body closes the support opening upon installation of the engaging projection in the support opening.
 9. The valve timing control apparatus according to claim 8, wherein the engaging projection is received in the engaging recess in a rotatable manner within a predetermined circumferential range to limit a variable range of the relative phase between the first rotator and the second rotator.
 10. The valve timing control apparatus according to claim 1, wherein the location on the outer side of the at least one gear portion and the planetary gear is placed radially outward of the at least one gear portion and the planetary gear.
 11. The valve timing control apparatus according to claim 1, wherein: the space is defined between an inner peripheral surface of the first rotator and an outer peripheral surface of the second rotator; and a plurality of protrusions radially inwardly protrudes from the inner peripheral surface of the first rotator toward the outer peripheral surface of the second rotator in the space.
 12. The valve timing control apparatus according to claim 11, wherein each of the plurality of protrusions is configured into a generally cylindrical body.
 13. The valve timing control apparatus according to claim 11, wherein each of the plurality of protrusions is configured into a generally planar quadrangular prism body.
 14. The valve timing control apparatus according to claim 11, wherein: the plurality of protrusions includes: a first row of protrusions, which are placed one after another at generally equal intervals in a circumferential direction of the first rotator; and a second row of protrusions, which are placed one after another at generally equal intervals in the circumferential direction of the first rotator on a downstream side of the first row of protrusions.
 15. The valve timing control apparatus according to claim 14, wherein the protrusions of the second row are staggered relative to the protrusions of the first row.
 16. The valve timing control apparatus according to claim 11, wherein a radial projecting amount of at least one of the plurality of protrusions is smaller than that of the rest of the plurality of protrusions. 